1. Field of the Invention
The invention relates to a separating device for winding devices for material webs, longitudinally divided into several partial webs, particularly those made of paper or the like.
2. Description of the Prior Art
In order to improve the web separation in so-called reel cutters after the cutting station, it is known to use so-called duo roll spreaders. Here, as a rule, two conventional so-called rotary stretchers are involved, i.e., rolls whose axis (and hence also their surface) is curved. The height of the arc, i.e., the radius of the deflection line, is adjusted to the particular application. Both rotary stretchers (also several rotary stretchers are possible) are arranged essentially parallel to each other and the planes spanned by the deflection lines are arranged essentially parallel to each other for the purpose of archieving a flawless functioning. Additional conditions for a flawless functioning are that the planes, spanned by the deflection lines, are always at a right angle to the entering or exiting web and the arcs, formed by the rotary stretchers, point in the same direction.
The extent of the total separation of all partial webs that can be achieved is a constant value for the respective initial situation. Thus, with an increasing number of partial webs, the spacing gaps that are realizable between them in a certain initial situation become increasingly smaller. For the rest, the extent of the achievable separation--on the one hand--depends on the radius of the deflection line of the rotary stretchers. The greater the deflection, i.e., the smaller the deflection radius, the greater the separation. On the other hand, the extent of the separation depends on how far (in the case of a constant axial distance of the two rotary stretchers) the web entering the separating device is distanced from the web exiting the separating device perpendicular to the direction of advance of the web. The greater this distance measure, described as the effective height (=H.sub.eff) , the greater the separation.
Depending on the total width of the web that has been longitudinally separated into partial webs, and, depending on the number of partial webs and possibly on additional parameters, it is necessary, from case to case, to change the dimension of the separation. Since the deflection of the rotary stretchers can be changed only with great effort, it is customary to change the effective height by pivoting the two rotary stretchers about the common pivot point. In order to meet the condition of rectangularity between the arcs of the rotary stretcher and the entering or exiting web, the alignment of these arcs with respect to the entering web, on the one hand, and the exiting web, on the other hand, must be changed during a sweep of the two rotary stretchers by means of subsequent adjustment. This is time-consuming and labor-intensive, since the rotary stretchers inside the machine are often difficult to access.
DE-B-200 75 69 discloses a separating device having at all four rolls, two of which are revolving rolls borne in a tiltable boom frame, two of which are flexed rolls borne in a swivelling cross of swivelling arms. The swivelling axis of the swivelling cross must be exactly in the middle between the axis of the revolving rolls, therefore the ends of the boom frame are stationary coupled with the revolving rolls. The amount of web separation is changed by altering the wrapping angle of a web around the flexed rolls. Maximal separation is achieved with a wrapping angle of 90.degree.. Therefore, the axis of one revolving roll is coupled with a corresponding flexed roll by alining arms with fork-shaped guidings.
A generic separating device is known from EP 0 431 275 A2 comprising a regulation mechanism which is fitted to correct the directional angles between the rolls and the web to desired values, preferably 90.degree., by means of rods being pitovable around their endportions and a swing mechanism, which is fitted to act upon the rolls to alter the deflection angles of the webs.